April 2nd, 2015
Most people have heard of probiotics related to the gastrointestinal tract. (Think about all the yogurt advertised to improve your digestion.) Probiotics are “live microorganisms [that] when administered in adequate amounts confer a health benefit on the host” (FAO/WHO, 2001). Probiotics interact with the bacteria that already reside in the host, a collection of microorganisms called the microbiome. The bacteria that line the intestines get a lot of attention, but the skin and upper respiratory tract also have their own resident microbial species which are important in maintaining the health of the host. Streptococcal strains in the upper respiratory tract can prevent some pathogens from infecting epithelial cells, which line the upper airways (Fiedler, 2013).
A recent study published in PloS ONE looked at the upper respiratory tract microbiome profiles of patients with pandemic H1N1 influenza to determine whether the microbiome changes during H1N1 infection (Chaban, 2013). The group of Canadian scientists examined samples collected from H1N1 patients using metagenomic profiling. This technique uses quantitative polymerase chain reaction (qPCR), the same technology used to analyze human DNA. In healthy people, the upper respiratory tract is predominantly colonized by one of three types of bacteria – Firmicutes, Actinobacteria, or Proteobacteria.
Actinobacteria and Firmicutes dominant hosts are more common, with Proteobacteria dominant individuals making up a small portion of the population. In H1N1 patients, Proteobacteria-dominated microbiomes were more common than had previously been seen in healthy subjects. The authors hypothesize that “influenza A infection may be associated with a more Proteobacteria-dominated upper respiratory tract microbiome”, but are quick to point out that more research is necessary before making any definitive statements. However, this work leads to exciting speculation about the possibility of probiotics as novel therapies. Maybe the upper respiratory tract microbiome could be changed with a nasal spray and we could avoid the annual flu shot.
Also read: Probiotic Yogurt Counteracts Fast Food Diet
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